In a pan on medium heat, add a splash of olive oil.
While pan is heating, chop all of your vegetables, add to pan once heated.
After sweating the vegetables (onions will be turning translucent), add ground beef and minced garlic, mixing with vegetables, then leave undisturbed for 2-3 minutes to brown.
Once the meat begins browning, add tomato paste, oregano and salt & pepper to taste, and a splash of red wine.
Sprinkle in parmesan cheese, adjust spice to taste, continue to cook until ground beef is done.
Butter the outside of both slices of bread.
Spread a tablespoon of ricotta on each slice of bread.
Place half of the meat mixture onto the bottom slice, then place your mozzarella cheese, and the other half of the meat.
Top with other slice of bread.
Fry in your pan until golden brown on each side (cover with lid to help melt cheese).